I believe it would be the first option but I'm not sure.
The formula for an average of three numbers is (x+y+z)/3. So if V equals the average, then we find the formula
V = (x+y+z)/3
We are now looking for x. We can divide each of the variables in the parentheses by 3, making the formula
V = x/3 + y/3 + z/3
So now bring the unwanted variables to the same side as V.
V - y/3 - z/3 = x/3
Now multiply both sides by 3 to find x.
3V - y - z = x
x = 3V - y - z
Distance = speed x time
Speed= 520÷10=52
52mi/hour
Step-by-step explanation:
2(x-3)=5(x-3)+10
=> 2x - 6 = 5x - 15 + 10
=> -6 + 15 -10 = 5x - 2x
=> 5x -2x = 15 - 6 - 10
=> 3x = 15 - 16
=> 3x = -1
